• build csfle without any gnu-unique flags, with the v3 GCC and the v4 gcc. Does the resulting binary contain any STB_GNU_UNIQUE symbols? If so, are they from the mongodb/third_party code, or are they from the toolchain C++ runtime?
• If it does contain them from mongo/third_party, does building our sources with fno-gnu-unique eliminate them? Does linking with -Wl,-no-gnu-unique eliminate them?
• If it does contain them from the toolchain C++ runtime, can Wl,-no-gnu-unique eliminate them by downgrading them from STB_GNU_UNIQUE to something else?
• If we cannot eliminate them easily (e.g. the toolchain ones persist despite Wl,-no-gnu-unique, are there issues when dlopen’ing the csfle.so library in the context of another library that has STB_GNU_UNIQUE symbols that should be resolved to, say, the system C++ runtime?

The above questions should be answered by using tools like nm and readelf for the first few, and LD_DEBUG for the latter.